title: Primary leptomeningeal lymphoma: International Primary CNS Lymphoma Collaborative Group report.
abstract: OBJECTIVE
  To evaluate clinical presentation, optimal diagnostic evaluation and treatment, and outcome in primary leptomeningeal lymphoma, a rare form of primary CNS lymphoma without parenchymal or systemic involvement.
  
  
  METHODS
  The International Primary CNS Lymphoma Collaborative Group, a multidisciplinary group of physicians with a particular interest in primary CNS lymphoma, retrospectively identified cases of lymphoma isolated to the leptomeninges as diagnosed by CSF cytology, flow cytometry, or biopsy, without systemic or parenchymal brain/spinal cord lymphoma or immunodeficiency.
  
  
  RESULTS
  Forty-eight patients were identified, with median age at diagnosis of 51 years and median Eastern Cooperative Oncology Group performance status of 2. Presenting symptoms were multifocal in 68%. Leptomeningeal enhancement was seen in 74% and CSF profile was abnormal in all cases. CSF cytology detected malignant lymphocytes in 67%. Flow cytometry identified monoclonal population in 80%, as did receptor gene rearrangement studies in 71%. Sixty-two percent had B-cell lymphoma, 19% T-cell, and 19% unclassified. Treatment varied and included fractionated radiotherapy (36%), systemic chemotherapy (78%), and intra-CSF chemotherapy (66%), with 66% receiving ≥ 2 modalities. Seventy-one percent had a favorable clinical response; ultimately, 44% received salvage treatment. Median overall survival was 24 months, with 11 patients still alive at 50 months follow-up.
  
  
  CONCLUSIONS
  Primary leptomeningeal lymphoma is a rare form of primary CNS lymphoma. Patients usually present with multifocal symptoms, with evidence of leptomeningeal enhancement and diagnostic CSF analysis. Although treatment is highly variable, patients have a better prognosis than previously reported and a subset may be cured.
authors.affiliation: From the Massachusetts General Hospital (J.W.T., T.B., R.A.B.), Boston; Mayo Clinic (E.P.F., B.P.O.), Rochester, MN; Hadassah Hebrew University Medical Center (T.S.), Jerusalem, Israel; Memorial Sloan-Kettering (A.O., L.D.), New York, NY; Yale University (J.B.), New Haven, CT; Saitama Medical University (R.N.), Japan; Kings College Hospital (F.P.), London, UK; University of Washington (M.C.), Seattle; LOC National Expert Center (K.H.-X., A.G.-A.), APHP, UPMC, Pitie-Salpetriere, Paris; Centre Leon Berard (J.-Y.B.), Lyon, France; Campus Benjamin Franklin (A.K.), Charite Universitätsmedizin Berlin, Germany; Department of Biostatistics (R.A.B.), Harvard School of Public Health, Boston, MA; and University of Virginia (M.-B.S.L., D.S.), Charlottesville.
authors.forename: Jennie W
authors.initials: JW
authors.lastname: Taylor
authors.forename: Eoin P
authors.initials: EP
authors.lastname: Flanagan
authors.forename: Brian P
authors.initials: BP
authors.lastname: O'Neill
authors.forename: Tali
authors.initials: T
authors.lastname: Siegal
authors.forename: Antonio
authors.initials: A
authors.lastname: Omuro
authors.forename: Lisa
authors.initials: L
authors.lastname: Deangelis
authors.forename: Joachim
authors.initials: J
authors.lastname: Baehring
authors.forename: Ryo
authors.initials: R
authors.lastname: Nishikawa
authors.forename: Fernando
authors.initials: F
authors.lastname: Pinto
authors.forename: Marc
authors.initials: M
authors.lastname: Chamberlain
authors.forename: Khe
authors.initials: K
authors.lastname: Hoang-Xuan
authors.forename: Alberto
authors.initials: A
authors.lastname: Gonzalez-Aguilar
authors.forename: Tracy
authors.initials: T
authors.lastname: Batchelor
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Blay
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Korfel
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Betensky
authors.forename: Maria-Beatriz S
authors.initials: MB
authors.lastname: Lopes
authors.forename: David
authors.initials: D
authors.lastname: Schiff
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016543:Central Nervous System Neoplasms / Q000134:cerebrospinal fluid / Q000175:diagnosis* / Q000401:mortality / Q000628:therapy*; D002648:Child; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008223:Lymphoma / Q000134:cerebrospinal fluid / Q000175:diagnosis* / Q000628:therapy*; D008279:Magnetic Resonance Imaging; D008297:Male; D008577:Meningeal Neoplasms / Q000134:cerebrospinal fluid / Q000175:diagnosis* / Q000401:mortality / Q000628:therapy*; D008875:Middle Aged; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult